Yup. And... I am probably wrong about the parallel interface. John describes it well. I was a comm jock once a long time ago before these were made. But I don't remember my line-level stuff. It would be normal for it to be parallel in an internal design like this because it is faster to drive these. But it does look like a load and latch interface to two logical busses.
On Wednesday, June 5, 2019 at 11:19:21 AM UTC-4, GastonP wrote: > > Most Arduino kits but the smallest ones (i.e.: Mini) and Raspberry Pi have > enough GPIO pins available to do it without need to resort to serial to > parallel. Of course you can use any of the I2C chips available too. My > philosophy is to adhere as much as possible to the KISS principle. > > On Wednesday, June 5, 2019 at 11:11:31 AM UTC-3, Keith Moore wrote: >> >> This is accurate and great detail. I believe it is simpler than you might >> think. This is just a parallel interface (times two). >> >> The work is done with the shifters and the data is pumped via a parallel >> interface from the processor as in the original design. >> I am just a software guy, but once I saw the trusty parallel chip, I >> figured it was a parallel interface. >> >> So how does one drive a parallel interface from Arduino/Raspberry? >> Probably via a serial to parallel converter board with a variant of IEEE >> 1284 output. I have not looked into this yet, but that's where I plan to >> start. >> >> Am I way off base? >> >> On Wednesday, June 5, 2019 at 4:47:46 AM UTC-4, andybiker wrote: >>> >>> Hi John, >>> The scans you posted answer all of the questions. >>> There is no "display controller" as you'd expect from the modern "fruit >>> machine" displays. >>> All we have on the board is latches and level shifters. >>> pins 16,18,19 control a shift register (TL5812) to select the digit >>> position to display (both displays selected at the same time) >>> there are then 4 latches - 2 for segments on top display, 2 for segments >>> on bottom display >>> These latch the 8 bit data bus (pins 4 to 11) to each level shifter. >>> the first 3 latches are internal to an 8255 (antique i/o port that I >>> last used in the early 80s) - selected with /A7 (pin3) low , /SEL4 (pin 13) >>> low and /WR (pin1) low /RD (pin 2) HIGH >>> A0 and A1 (pins 14 + 15) select which one of the 3 latches to use (and >>> initialise the 8255) >>> As this part only has 3 latches and we need 4, an extra latch has been >>> bolted on in the form of IC2 (74ls273) >>> This is selected with /SEL4 (pin 13) low, /A7 (pin 3) HIGH, /WR (pin1) >>> low >>> (I think reset should be kept high - need to check data sheets) >>> Supplies are 47v, 5v, 4.5vAC for the filament. >>> >>> Data sheets are available for all of these chips. >>> I suspect that driving one is "a full time job" for something like a >>> simple arduino. >>> >>> I hope my ramblings help someone, >>> Cheers, >>> Andrew >>> >>> >>> On Tuesday, June 4, 2019 at 9:52:24 AM UTC+1, Nixcited delighted wrote: >>>> >>>> I now have my displays and the schematic. >>>> >>>> I have scanned relevant manual pages, power supply, interconnect, >>>> display board and component identification. >>>> >>>> https://www.dropbox.com/s/bltgd4w4o9gonuy/Alvin_G_Display.zip?dl=0 >>>> >>>> John S >>>> >>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a9897769-2e16-46bb-95be-6c4b84f92031%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
